nfs/blocklayout: add support for NVMe

Look for the udev generated persistent device name for NVMe devices
in addition to the SCSI ones and the Redhat-specific device mapper
name.

This is the client side implementation of RFC 9561 "Using the Parallel
NFS (pNFS) SCSI Layout to Access Non-Volatile Memory Express (NVMe)
Storage Devices".

Note that the udev rules for nvme are a bit of a mess and udev will only
create a link for the uuid if the NVMe namespace has one, and not the
NGUID.  As the current RFCs don't support UUID based identifications this
means the layout can't be used on such namespaces out of the box.  A
small tweak to the udev rules can work around it, and as the real fix I
will submit a draft to the IETF NFSv4 working group to support UUID-based
identifiers for SCSI and NVMe.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/fs/nfs/blocklayout/dev.c b/fs/nfs/blocklayout/dev.c
index 221781fb9cf14b93a72ea8ab27329bf1c4ea70d2..6252f44479457b42fa69c79db7289fb6e1b55952 100644 (file)
--- a/fs/nfs/blocklayout/dev.c
+++ b/fs/nfs/blocklayout/dev.c
@@ -404,6 +404,8 @@ bl_parse_scsi(struct nfs_server *server, struct pnfs_block_dev *d,
        bdev_file = bl_open_path(v, "dm-uuid-mpath-0x");
        if (IS_ERR(bdev_file))
                bdev_file = bl_open_path(v, "wwn-0x");
+       if (IS_ERR(bdev_file))
+               bdev_file = bl_open_path(v, "nvme-eui.");
        if (IS_ERR(bdev_file)) {
                pr_warn("pNFS: no device found for volume %*phN\n",
                        v->scsi.designator_len, v->scsi.designator);